A known scanning probe system with multiple probes is described in US2010/0186132. The probe assembly comprising a carrier with at least three probes, each probe having a tip that is located on a plane that is common to the probe tips and that is moveable from this plane. The probes are substantially identical and the assembly also includes addressing means adapted to select one of the probes for relative movement with respect to a majority of the remainder of the probes. Examples of suitable arrangements for actuating and detecting multiple probes are described in US2015/0219685 and US2015/0219686.